Nowadays, twisted nematic (TN) LC Panel (or TN LC cell) is being widely used in various fields, especially in display technologies. FIG. 1 illustrates a conventional TN LC panel. Glass substrate 11 and glass substrate 12 are arranged in parallel with a predetermined distance therebetween. On the inner surfaces of substrate 11 and substrate 12, transparent electrodes 13 and 14 are provided respectively. Further, on the outer surfaces of the electrodes 13 and 14, alignment layers 15 and 16 are provided respectively, and the rubbing directions of alignment layers 15 and 16 are perpendicular to each other. TN liquid crystal is filled between alignment layers 15 and 16.
When there is no voltage applied between the transparent electrodes 13 and 14, linearly polarized lights entering the TN LC panel via an alignment layer in a direction parallel to the rubbing direction of the alignment layer, the TN LC panel will change the polarization direction of the lights by 90 degrees coming out of the TN LC panel. However, when a voltage applied between the transparent electrodes 13 and 14 is greater than or equal to a threshold voltage, TN molecules re-align the long axis along the direction of the electric field between transparent electrodes 13 and 14, and the TN LC panel does not change the polarization of the entering lights.
Further, conventional 2D/3D switchable display systems, such as one disclosed in Chinese patent application no. CN101387758A, often position an above-mentioned TN LC panel in front of a regular display screen as the 2D/3D switching device. The 2D/3D display is switched by regulating polarization directions of lights passing the TN LC panel through controlling voltages applied to the TN LC panel. Thus, the 2D/3D display switching is often done for the entire display screen and not for different portions of the display screen.
To solve the above problem, other conventional 2D/3D switchable display systems use a thin film transistor (TFT) TN LCD panel as the switching means. Because, in the TFT TN LCD panel, pixels can be individually addressed, 2D/3D switching can be realized on portions of the display screen. However, TFT TN LCD panels are complex and expensive, and often need to place non-transparent TFT circuit wires and grating wires, etc., on the substrates, which may need to be covered by a black matrix. Thus, an effective display area may be reduced, the aperture ratio may be reduced, and the existence of the black matrix may impact image display quality. However, if removing the black matrix, bright lines may appear along the electrodes, which may also impact image display quality.
The disclosed methods and systems are directed to solve one or more problems set forth above and other problems.